For the past couple of years, a street cleaning vehicle has been washing, brushing and vacuuming the streets of Basel in northwest Switzerland. While there's nothing unusual about that, what is noteworthy is that the vehicle, known as the CityCat H2, is powered completely by hydrogen. The street sweeper is part of a project to practically test the feasibility of hydrogen-powered vehicles under real-world conditions and the results from the trial indicate that, although hydrogen-powered vehicles can save energy, are environmentally friendly, and technically feasible, the prices of fuel cells, pressurized storage tanks and electric drives must all drop significantly before such vehicles are cost-effective.

The project is being conducted by a team consisting of researchers from Empa, the Paul Scherrer Institute (PSI), vehicle manufacturer Bucher Schoerling, electric drive specialist Brusa, hydrogen manufacturer Messer Schweiz, and the city of Basel Environment and Energy Department. The CityCat H2 first took to the streets of Basel in 2009 after 18 months of development and ran into problems early on.

"It became clear relatively quickly that the fuel cell system, which had been developed as a one-off specially for the project, was not yet ready for use in a real-life setting," explains project leader Christian Bach, head of Empa's Internal Combustion Engines Laboratory. "On top of that, the various safety systems kept interfering with each other and bringing everything to a halt."

The team replaced the initial fuel cell system with a more mature unit and fitted the vehicle with a single centralized safety module. Shortly after these initial repairs, the voltage converter between the fuel cell system and the battery died, and the electric motor drive and two cooling water pumps had to be replaced. Since these components were tailor-made for the vehicle and took some time to be delivered, the vehicle was off the road for some time.

However, since returning to the streets in the Swiss summer of 2011, the team says the vehicle has been much more reliable and has only needed to be taken out of service once, due to a defective water pump. In fact, the vehicle has been running so reliably for the past three months that Basel's city cleaning services have been able to use it on an everyday basis just like a "normal" vehicle.

Findings of the trial

According to the project team, over the course of the trial the CityCat H2 consumed less than half the fuel of its diesel-powered contemporaries. Instead of 5 to 5.5 liters of diesel per hour - which equates to energy consumption of 180 to 200 MJ per hour - the hydrogen-powered vehicle consumed only 0.3 to 0.6 kg of fuel per hour - or 40 to 80 MJ per hour.

And although the hydrogen used to power the vehicle was produced using fossil fuels, the vehicle still boasted a 40 percent reduction in CO2 emissions when compared to similar diesel-powered vehicles. This would obviously be further reduced if the hydrogen were produced using energy from renewable sources.

The trial also showed that the vehicle was user-friendly and safe, with drivers refueling it themselves at a mobile hydrogen fuel station. These refueling stations, along with the garage where the vehicle was parked, were fitted with a hydrogen monitoring system, which detected no leaks throughout the trial. The vehicle also proved much quieter than a diesel vehicle - even with the suction system and brushes operating.

According the to project team, the only real practical disadvantage of the hydrogen-powered vehicle was that there wasn't enough waste heat generated by the fuel cell and electric motor to keep the driver's cabin warm on cold days. A heater unit was fitted to the driver's seat to address this.

The other big downside was the cost, with the team saying a hydrogen-powered vehicle of this sort is around three times as expensive as a conventional diesel-powered vehicle. However, they point out that the cost of fuel cell systems alone have dropped by a factor of ten in just the past few years, and that this trend is continuing.

The Basel trial of the CityCat H2 is due to end this month, with the vehicle then being moved to St. Gallen in eastern Switzerland, where further practical trials will be carried out. This will allow more testing of the vehicle under real-world usage conditions and let the team study how the various components behave as they age.

Of course, hydrogen-powered municipal vehicles are just the tip of the iceberg with a number of major automotive players, including Honda, BMW and Mazda, already dipping their toes into the hydrogen-powered pool. And with the numerous research efforts underway to develop a clean and cost-effective way to produce hydrogen on a mass scale, hydrogen-powered vehicles could soon be a viable transportation option that offers the local emission-free benefits of an electric vehicle, with the range of traditional gasoline-powered vehicles.

Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

All you hear when the sweep the streets around my house is the vacuum and brushes. But I haven't seen it blow a black cloud so I can't swear its a diesel.

Don't worry about CO2 emissions AGW is a fraud.

Slowburn 14th March, 2012 @ 03:46 am PDT

Great story, it's encouraging to see this progress. AGW is real, CO2 emissions are important and scientists find new facts to support it every day.

The Hoff 14th March, 2012 @ 07:32 am PDT

@Slowburn, Hardly a single Gizmag article goes buy without your comment. You seem to make it your job to find as many negative comments as possible, even if you have to invent stuff to say that has no basis in fact. I must say that you are the biggest detraction there is from my enjoying reading Gizmag. Most places would just ban a troll like you. I can't find a +/- button for posts here. Too bad, well consider this a "-1" for 90% of your posts. They are not appreciated by me. In the meantime, I will institute my personal ban on you not reading any future comments by you.

Now if you would like to research the facts of an article before posting, and add some valuable insights (positive or negative), then I would appreciate them. Think about what you can do to add value for the CO2 you are breathing into the atmosphere. ;-)

see3d 14th March, 2012 @ 11:16 am PDT

Regardless if AGW is real or not, many of the "side effects" that often come with reduced CO2 emissions (less SO2, NOx, soot, heat pollution, more energy independance, long-run economic savings) would be undeniably beneficial to both human and environmental health. Anyway, hats off to the city of Basel for not being afraid to try something new.

Forward Thinker 14th March, 2012 @ 02:17 pm PDT

I hate to sound like a "Debbie Downer", but, the major selling point of Hydrogen Powered vehicles is? They only emit water vapor! And where do they operate? On concrete or asphalt covered surfaces, acting as heat sinks that create updrafts that send the vapor skyward into the atmosphere, thereby contributing to a further "Warming" of the planet! (Remember Clouds? Think of L.A., Chicago, or NYC as a Louisiana Swamp in August. If the alarmists are right, that is.)

Myron J. Poltroonian 14th March, 2012 @ 04:01 pm PDT

gotta love Slowburn willing to condemn his grand children to death from a dying planet, only a moron, (no offense to anyone, trying to be PC here) could think our activities could not affect global climate. Is it worth the chance That You Are WRONG, ask yourself that.

Bill Bennett 14th March, 2012 @ 08:14 pm PDT

When the people who propose an idea destroy their records rather than let other people see them. When they conspire to keep rival views out of the journals. When they attack the reputation of the people presenting dissenting views without talking about the evidence. Get caught presenting intentionally false data. preach raising sea levels and then buy ocean front properties. I believe they are lying to me.

Slowburn 15th March, 2012 @ 07:14 am PDT

This is really sounds great. can you please give me the full features of this great vehicle.